I think that there was a short segment about them in tech section of new HR mag. They are made for TH400's, and can have two stall speeds (e.g. 1800 and 5000 rpm) that can be switched between via manual switch or computer operation.

Just wondering if any of you tech heads have thought about such an idea and it's practical apps.

 

They were BOP, requiring an adapter to bolt to a Chevy engine. The TH400 has to be made for it, you can't adapt a non-dual 400 to be dual AFAIK. I don't recall stall speeds that were that far apart, but the intent was to provide high stall for power situations, and low stall for cruise.

They were the rage to some people back in the 70's & 80's (Kenney-Bell, for instance), but a locking torque convertor provides a better means to the end, and is a lot simplier.

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82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 2.73 open. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, exhaust, paint, etc.).
57 Bel Air, my 1st car. Currently 396 .030 over, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

The converter is called a switch pitch. It stalled around 1800 and 4000.

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Stephen's racing page

87 IROC-Z Pro ET Bracket Race Car and knocking on the SuperPro ET class
383 stroker (carbed) with double hump cast iron heads and pump gas
LS6 Big Block buildup now in progress

Best results before the engine blew up
Best ET on a time slip: 11.857
Best corrected ET: 11.163
Best MPH on a time slip: 117.87
Best corrected MPH: 126.10
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!

Member of the Calgary Drag Racing Association

 

These are still available from Poston industries (the Buick guys). Your Trans needs to have a special input shaft or something. I have a 4 year old catalog around here somewhere. I recall cost was about $450 for the convertor and you had about 3 choices for stall speeds. Poston also sold complete trans/covt. combination and I remember the price being reasonable.

Maybe Pro-built has an opinion.

Zee